The contents of Application No. TOKUGANHEI 9-308953, with a filling date of Nov. 11, 1997 in Japan, are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a wiper device for a vehicle, and particularly to a wiper device for a vehicle preferably usable for a vehicle provided with a structure of a so-called concealed wiper type in which an upper portion of a wiper unit is covered with a rear end portion of an engine hood.
2. Description of the Related Art
In a vehicle provided with the structure of the so-called concealed wiper type disclosed in Japanese Patent Application Laid-Open Publication No. 5-270362, an end portion of an engine hood extends outwardly near a lower side portion of a front window panel, thereby covering an upper portion of a wiper unit.
However, in such a structure, since the rear end portion of the engine hood becomes close to the upper end portion of a wiper pivot of the wiper unit, the rear end portion of the engine hood is brought into contact with the wiper pivot when a collision load acts on the rear end portion of the engine hood from the upper side of the vehicle body downward to the lower side of the vehicle body at a time of collision of the vehicle or the like, so that the engine hood tends to be prevented from freely deforming downward. That is, such a restriction of the deformation corresponds to a restricting condition in the case of desiring to increase an absorption amount of the collision energy.
An object of the present invention is to provide a wiper device for a vehicle which can improve an absorption characteristic of a collision energy without substantially restricting a deformation of a rear end portion of an engine hood to a lower side of a vehicle body by means of a wiper pivot when a load due to a collision or the like acts on the rear end portion of the engine hood from an upper side of the vehicle body (corresponding to an outer side of the vehicle body) to the lower side of the vehicle body (corresponding to an inner side of the vehicle body).
That is, the wiper device for the vehicle in accordance with the present invention is provided with a wiper motor, a wiper pivot connected to the wiper motor, and a pivot holder having a base portion attached to the vehicle body and a bearing hole pivotally supporting the wiper pivot in a rotatable manner.
In this case, the wiper pivot can rotate around the pivot axis by use of a drive force from the wiper motor, and the wiper pivot extends so as to project toward the outer side of the vehicle body and has a cutout portion, that is, a groove portion. Further, a C ring is attached so as to be engaged with the cutout portion of the wiper pivot.
In the structure mentioned above, it is further constructed such that the C ring engaged with the cutout portion is expanded so as to move apart from the cutout portion when a load equal to or more than a predetermined value acts on the wiper pivot due to a collision or the like, thereby moving the wiper pivot to the inner portion of the vehicle body.
Accordingly, in the wiper device for the vehicle in accordance with the present invention, when the load due to a collision or the like acts on the rear end portion of the hood member typically corresponding to an engine hood from the outer side of the vehicle to the inner side thereof, and more particularly, from the upper side of the vehicle body to the lower side thereof, a deformation of the rear end portion of the hood member to the lower side of the vehicle body is substantially made free by means of the wiper pivot structured in the above manner, thereby improving the absorption characteristic for the collision energy in the case of a collision or the like. Here, with respect to the absorption of the energy applied at a time of a collision or the like, the energy absorption is caused not only by a slide resistance when the wiper pivot is released from the pivot holder but also at a time of the expanding motion of the C ring.
In this case, more specifically, the wiper pivot is covered with the hood member typically corresponding to the engine hood in the outer side of the vehicle, and the load at a time of a collision or the like acts on the wiper pivot through the hood member.
Here, in the wiper device for the vehicle in accordance with the present invention, particularly, it is preferable that the C ring has a substantially circular cross sectional shape for a simplicity of the structure and a reliability of the expansion motion thereof. And the substantially circular cross sectional shape includes an oval cross sectional shape capable of performing substantially the same expansion motion as well as the circular shape.
Further, in the wiper device for the vehicle in accordance with the present invention, particularly, it is preferable to structure such that the cutout portion is provided in a portion of the wiper pivot projecting to the upper side of the vehicle body from the pivot holder, at least a wall surface of the cutout portion positioned in the upper side of the vehicle body is a surface inclined to the upper side of the vehicle body from a bottom portion of the cutout portion, and the C ring is deformed to be expanded in such a manner that it moves apart from the cutout portion so as to move the wiper pivot to the lower side of the vehicle body when the load equal to or more than the predetermined value acts on the wiper pivot, because the inclined wall surface surely generates a guide effect when the C ring is expanded. Of course, also in this case, generally, the outer side of the vehicle body corresponds to the upper side of the vehicle body, and the inner side of the vehicle body corresponds to the lower side of the vehicle body.
Further, as the cutout portion, the structure having a substantially V-shaped cutout shape is preferable for a simplicity on manufacturing and a reliability of the expansion motion.